How important is it to have RDNS entries match the nameserver pointing to that IP - i.e. ns1.mydomain.com - and why?

I'm sharing an IP between a nameserver, ns1.domain.com and an IP based site which will in the next 6 months have a secure cert for ordering. I'm trying to decide whether to make the rdns entry domain.com to match the site or ns1.domain.com to match the nameserver pointing to this IP.

I'd match the site. Some clients will think your more trustworthy if your SSL based site has matching forward and reverse records.

Also, I *believe* that RFC's require that forward A records match the PTR records. I'm almost positive I read that, but I'm not too interested in searching through RFC archives to find it.

Anyhoo, it's not really strictly enforced, but it is somewhat nice.